1. Technical Field
Embodiments of the present invention are related to semiconductor devices, and more particularly to voltage supply devices capable of maintaining an output voltage at a predetermined level.
2. Description of Related Art
Semiconductor devices commonly operate based on a power voltage Vcc that is provided from an external source. The voltage provided from an external source to the semiconductor devices has a regular voltage level. However, in order for the semiconductor devices to operate normally, various voltage levels are required. For example, in a NAND flash memory device, a read voltage, an erase voltage, a write voltage and a pass voltage all have different voltage levels. A voltage supply device is therefore employed to receive the regular voltage and to generate multi-level voltages. The voltage supply device commonly receives a voltage from an external source, and internally generates voltages that are required by the semiconductor devices for normal operation.